Generally, a foam production pump is widely used for shaving cream, hair mousse, facial cleansing cream, liquid soap, body shampoo, industrial multi-purpose cleanser, facial cleanser, etc. Also, the foam production pump is generally constructed in a structure to mix liquefied contents with an appropriate amount of gas and extrude the mixture thereby producing foam.
However, a conventional foam production pump has problems in that the foam production pump is filled with additional compressed gas, and contents are not discharged out of the foam production pump but only the compressed gas is discharged out of the foam production pump when the foam production pump is inclined. Also, the use of the compressed gas causes environment-related problems. In addition, the compressed gas may catch fire or explode. For this reason, the structure in which the foam production pump is filled with the compressed gas requires durability and complicated components, which raises the manufacturing costs of the foam production pump.
Therefore, research has been made on a foam production pump that is capable of appropriately mixing contents with external air introduced into the foam production pump to produce foam, and technologies related to the foam production pump have been continuously developed.
The foam production pump includes a housing forming the external appearance of the pump, the housing being configured to separately store external air and contents, a closure configured to mount the housing to a container, a mixing unit for mixing the contents with the air, a stem communicating with an outlet port of a cap, the stem being configured to move up and down along the housing, a shaft for guiding the up-and-down motion of the stem and connecting the step to the cap, a piston mounted to the stem for performing an up-and-down motion along an inner wall of the housing, a compression spring mounted at the lower inside of the housing, and a ball for opening and closing an inlet port formed at the lower end of the housing.
However, the conventional foam production pump has several problems.
First, the compression spring is located in a flow channel of the contents, with the result that the compression spring comes into contact with the contents. Consequently, the compression spring may be deteriorated, and the deteriorated compression spring causes the contamination of the contents.
Second, the ball, which serves to open and close the inlet port formed at the lower end of the housing, performs an operation for opening and closing the inlet port based on the change of the pressure in the housing and the gravity, with the result that the ball does not rapidly respond to a pumping action, and it is difficult for the ball to provide a high sealing force. Consequently, some of the contents may leak out to the container during pumping. Furthermore, the ball does not perform a rapid opening and closing operation, which decreases a pumping force.
Third, a structure to introduce and store external air and a structure to introduce air from the housing to the mixing unit that mixes the contents with the air when pumping are further required in addition to the structure to pump the contents, unlike a general hand-operated spray pump. As a result, the number of components constituting the foam production pump increases, and therefore, the structure of the foam production pump is complicated, whereby the foam production pump may frequently break down when in use.
Although various structures to solve the above-described problems have been developed, few of them provide a satisfactory result. Therefore, there is a high necessity for a technology that is capable of fundamentally solving the above-mentioned problems.